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25 December 1992, Volume 9 Issue 4 Previous Issue    Next Issue

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OBJECT-ORIENTED PROGRAMMING ZHANG Shu-yu, HAO Bai-lin 1992, 9(4): 343-345.  Abstract ( )   PDF (263KB) ( )   OOP is becoming as important as structured programming in the 1970s. Relavance of OOP to computational physics is discussed on the examples of multiwindow systems, a seismicity-analyzing system, and a system for qualitative study of ODE's. The C++ language as a main tool for OOP is also briefly touched.

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HIGH SPEED SCIENTIFIC COMPUTATIONS AND MASSIVE PARALLEL COMPUTER Li Guqjie 1992, 9(4): 346-350.  Abstract ( )   PDF (483KB) ( )   In this article, we analyze the requirements of "Grand challenges" problems in high speed scientific computations for massive parallel processing (MPP) systems, compare vector supercomputers with MPP, introduce the present state of the art and key technology of MPP, and discuss the issues of parallel computational models, parallel algorithms, and parallel programming environment. The purpose of this article is to call attention of reserchers in computional physics area to the MPP.

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COMPUTATIONAL METHODS PRESERVING SYMPLECTIC STRUCTURE FOR HAMILTONIAN EQUATIONS Qin Mengzhao 1992, 9(4): 351-353.  Abstract ( )   PDF (208KB) ( )   In this paper, some untations and facts about symplectic geometry and Hamiltonian mechanics are given. Then various symplectic difference schemes are considered.

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NUMERICAL SIMULATION OF THE FIRE-SPREAD UNDER A NUCLEAR BURST Zhang Suochun, Lei Guangyao, Wang Yiren, Huang Weizhang 1992, 9(4): 354-356.  Abstract ( )   PDF (242KB) ( )   In this paper, we are concerned only with computer simulation of the fires of buildings ignited on urban areas produced by a nuclear burst. The numerical test is obtained sorne qualitative results for the simplest model by using the parameters of fire-spread from Japanese Hiroshima.

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CARBON DIOXIDE CONTROL CARBON-POTENTIAL MODEL FOR GAS CARBURIZATION TECHNOLOGY Yang Shaohua 1992, 9(4): 359-360.  Abstract ( )   PDF (161KB) ( )   In this paper, a Carbon dioxide control Carbon-potential model for gas carburization technology was suggested, and i

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COMPUTER SIMULATION OR THREE-DIMENSIONAL PROBLEM OF AN OIL-GAS BEARING BASIN AND ITS NUMERICAL ANALYSIS Yuan Yirang, Yang Danping, Wang Wenqia 1992, 9(4): 361-365.  Abstract ( )   PDF (319KB) ( )   Computer simulation for evolutionary history of an oil-gas bearing basin is to repeat its geological and thermodynamic evolutionary history on a computer. The mathematical model of basin simulation is characterised by an initial-boundary value problem of nonlinear partial differential equations on the abnormal pressure and the paleo-temperature of the formation. In the present paper, numerical method for three-dimensional proposed, the analysis on their stability and a numerical result for a practical model is given also. The results show that the abnormal pressure and the paleo-temperature computed are reasonable and display physical characteristics clearly as well.

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THE CALCULATION ON NONLINEAR TORSIONAL VIBRATION RESPONSE OF ENGINE SHAFTING Liu Gongming, Zhang Zhihua, Wang Zhiqiu, LiuZhigang 1992, 9(4): 367-370.  Abstract ( )   PDF (308KB) ( )   In this paper, some kinds of the schemes are investigated combing with the characteristics of engine shafting. Analysis result shows that the Newmard's method and the wilsion's method are more suitable for solving torsional vibration problems. A general computing programme is developed using both methods mentioned above, and two examples are presented.

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REAL NUMBER LATTICE GAS SIMULATION OF FLUID FLOW AROUND A SQUARE CYLINDER Shi Weiping, Hu Shouxin 1992, 9(4): 371-372.  Abstract ( )   PDF (151KB) ( )   We discuss a alternative technique to the lattice gas automata for the study of viscous flows. It is shown that the lattice gas automata with real number population deriving from the HPP model being free from microscopic fluctuations. provides a new appealing tool to simulate viscous flows. Numerical results pertaining to a two-dimensional flow past a square cylinder are reported and compared with experimental data available in the literature.

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A LATTICE GAS MODEL WITH GRAVITY Liu Zhi, Hu Shouxin 1992, 9(4): 373-374.  Abstract ( )   PDF (146KB) ( )   In this paper, a lattice gas mode! is proposed to simulate gravity. We evaluated the average of gravity and obtained a macroscopic parameter k.When 0≤k≤0.02, The pressure distribution obtained is in agreement with the theoretical predictions.

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THE DYNAMIC ELASTIC-PLASTIC DEFORMATION OF THE FREE CONICAL SHELL Gui Xingen 1992, 9(4): 375-376.  Abstract ( )   PDF (159KB) ( )   This work with ABAQUS code is a computational solution of the free conical shell subjected to a kind of transient pressure in some area. The material of this shell includes strain-rate sensitivity. This paper demonstrates its main patterns in several milliseconds of the response. The patterns are:the stronger stresses, the plastic yielding is mostly taken in the loading area, the wave phenomenon of the circumferential stresses, the wave phenomenon of the axial stresses, the deflections of the whole shell are "breathing" and corrugated.

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NUMERICAL ANALYSIS OF CHARACTERISTICS OF ALUMINIUM DUST EXPLOSIONS IN CLOSED SPHERICAL CHAMBER Ding Dayu, Fan Baochun, Tang Mingjun 1992, 9(4): 377-381.  Abstract ( )   PDF (354KB) ( )   Numerial methods,including Lagrangian's transformation, physical splitting and self-adaptive grid technique, are used for enlarging domain of calculation and simulating the whole process of aluminium dust explosion in 20 litre closed spherical chamber in this paper. The results from simulation are in good agreement with measured experiment results.

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NUMERICAL ANALYSIS OF CONVECTION AND DIFFUSION IN ARBITRARY NONORTHOGONAL COORDINATES Chen Hanping, Shi Zhengjun 1992, 9(4): 382-386.  Abstract ( )   PDF (372KB) ( )   In the paper the finite control volume integral formulation are derived in three dimensional nonorthogonal coordinates. The curved coordinate velocities on the control volume surface are taken as conveying ones and the Cartesian coordinate velocities at the center of the control volume as the variables of momentum equation. As an example, natural convection are calculated in two and three dimensional domains of eccentric cylinders and spheres.

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NUMERICAL SIMULATION OF TRANSONIC TWO-PHASE REACTIVE FLOW IN HIGH-LOADING EXPLOSIVE BEDS Jiang Xi, Wang Sunyuan 1992, 9(4): 387-392.  Abstract ( )   PDF (408KB) ( )   The continuous medium mathematical modeling of two-dimensional unsteady transonic two-phase reactive flow of explosive particles in high-loading beds is investigated. The SIMPLE method is successfully utilized for two-dimensional numerical calculation of the Defagration-to-Degonation Transition (DDT) processes in high-loading explosive beds. Special treatment for transonic flow and derivation of pressure correction equation for compressible fluid are presented. As an example, the calculated results for non-primary-explosive detonator show that this method weakens the numerical oscillation of transonic 2D-two-phase flow more effectively.

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RANDOM WATER WAVE FORCES ON GROUP CYLINDERS Tao Jianhua, Dou Xinyu 1992, 9(4): 393-394.  Abstract ( )   PDF (157KB) ( )   In this paper, by using the method of establishment a transfer function, the wave forces spectra on cylinders and the characteristics values are obtained from in incident wave spectra. The JONSWAP spcetra in used as a incident frequency spectra the Directional distribution function is square cosinusoidal funcation. The wave forces coeficients is two to four cylinders with different arrangment is computated wich can by used for engineering design. A comparison of computational and experimental results of single cylinder with frequency spectra is made and the agreement is satisfactory.

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NUMERICAL SIMULATION OF ODD SUBHARMONIC BIFURCATIONS IN POWER SYSTEMS Lai Dingwen 1992, 9(4): 395-398.  Abstract ( )   PDF (297KB) ( )   In this paper, some unkown physical processes in power systems are dissclosed by using the methods of Runge-Kutta and Galerkin. Such as the connection between the low-frequency resonances and the abnormity of magnetic hysteresis loop, the polarization of subharmonic bifurcations, the frequency region where the subharmonic resonances together with harmonic resonances exist and so on.

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NUMERICAL SIMULATION OF HEAT CYLINDER IN CROSS-FLOW Wang Jian, Tao Zhengwen, Lei Yunlong, Fan Weicheng 1992, 9(4): 399-401.  Abstract ( )   PDF (210KB) ( )   Employing the Boundary-Fitted Orthogonal Curvilinear Coodinate Systems, this paper tries to make the numerical simulations of a cold or heat cylinder in cross-flow at various Re numbers with the fundamental equations of hydromechanics and heat transfer. The comparisions of results of numerical solution with the experimental values are quite good.

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BUILDING ENERGY SAVING MODELS AND CALCULATION Zhang Licun, Xu Hui 1992, 9(4): 407-409.  Abstract ( )   PDF (232KB) ( )   At the base of nonsteady heat transfer theory, using modern count-physical method, the applicable mathematical models and physical models are set up and the reasonable boundafy conditions was given. It was indicated by the numerical calculation on the computer VAX11/785 that the temperature inside room could reach 14℃ at the area of Zhengzhou without heating.

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A METHOD FOR SOLVING THE DAM SEEPAGE FREE-BOSMDARY PROBLEM Zhan Tongsheng 1992, 9(4): 411-412.  Abstract ( )   PDF (145KB) ( )   In this paper, a transformation is given, which transformed the dam seepage free-boundary problem into a fixed-boundary problem of a quasi-Liner elliptic equations on a rectangular (as 2-dimension) or cubic (as 3-dimension) doma in. The latter problem is solved easily to use the finite-difference method and the SOR arithmetic. The method is given in this paper, is suitable for 2-dimension or 3-dimension and at that time there are a well.

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THE SPOT DIAGRAM ENERGY DISTRIBUTED CURVE AND THE GEOMETRIC OPTICAL TRANSFER FUNCTION Wang Qi 1992, 9(4): 413-414.  Abstract ( )   PDF (169KB) ( )   In this paper, the numerical methods are given for calculating the geometric optical transfer functions and the spot diagrams and the energy distributed curves by using Bessel function of order zero and numerical integration and Spline interpolation. These methods are of advantage to ensure accuracy and to save calculation.

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MODIFIED BOUNDARY ELEMENT TECHNIQUE FOR EIGENVALUE PROBLEMS Song Bin, Fu Junmei 1992, 9(4): 415-416.  Abstract ( )   PDF (131KB) ( )   A modified boundary element technique is proposed for the investigation of eigenvalue problems. In the approach, the foundamental solution corresponding to Laplace's equation is employed for Helmholtz's equation, thus the matrices in the formed boundary equation implicitly contain no eigen parameter. Therefore, this method only requires a small computer memory, and decreases the computation time.

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A NETWORK MODEL AND ALGORITHM FOR THE SHORT TERM ECONOMIC OPERATION OF THE THREE GORGES CASCADE HYDROELECTRIC SYSTEM WITH TRANSMISSION POWER TO MULTIREGTIONS Duan Yurong, Xu Mingde, Liu Jianhua 1992, 9(4): 417-422.  Abstract ( )   PDF (401KB) ( )   This paper, based on the characteristics of the Three Gorges Cascade Hydroelectric System, establishes a new short term economic scheduling network model for a cascaded hydroelectric system that transmits power to multiregions. A method combined with linear and nonlinear minimum cost network flow algorithms is used to solve the problem of load dispatch among the cascaded plants. In this paper, the short path algorithm with the data structure which is marked to arcs of the network saves the computational time and the storage space. The result that is computed on the microprocessor IMB PC/XT with FORTRAN language programs indicates that the model and the algorithm is the paper are correct.

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AN EFFICIENT IMPLICIT-EXPLICIT SCHEME AND AN IMPROVED LU SCHEME FOR 3D EULER SOLVER Wang Baoguo, Bian Yingui 1992, 9(4): 423-425.  Abstract ( )   PDF (186KB) ( )   This paper presents two schemes for solving three-dimensional Euler equations. These schemes are:(1)an efficient implicit-explicit scheme. It is used to treat the spanwise derivatives explicitly and the orther spatial derivatives implicitly, (2) an improved LU scheme for 3D flow. The two schemes are presented based on Jameson Turkel's LU decompositions and Harten's TVD concept. Numerical results indicate that these schemes are efficient and can generate good shock resolution for solving steady-state problem.

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EXACT CALCULATION OF QUANTUM MECHANICS FOR INELASTIC ATOM-MOLECULE SCATTERING Ren Tingqi, Wang Mingquan, Ding Shiliang 1992, 9(4): 426-428.  Abstract ( )   PDF (216KB) ( )   The time-dependent quantum mechanical method applied to inelastic atom-molecule scattering is presented and examined in interaction picture. The method is not only extremely accurate but is more efficient than the CC method.

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THE DIFFERENCE METHOD FOR NO INITIAL CONDITION DIFFUSION PROBLEM Wang Ruyun, Fang Baorong 1992, 9(4): 429-430.  Abstract ( )   PDF (142KB) ( )   In this paper, we design a kind of two levels five points explicit difference scheme for no initial condition diffusion problem. This kind of scheme not only allows the greater time step length, but also has the greater precision.

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A SUMMARY OF NUMERICAL COMPUTATION FOR SPECIAL FUNCTIONS Zhang Shanjie 1992, 9(4): 431-436.  Abstract ( )   PDF (423KB) ( )   In the paper, special functions frequently encountered in science and engineering are introduced. The computation of the values of Bessel function and elliptic integrals are taken to be the examples, and some common algorithms for computing most special functions, such as series expansion for small argument, asymptotic approximations for large argument, polynomial approximations, recurrence formulas and iteration method, are discussed. In addition, the determination of zeros of some special functions, and the other questions related to numerical computation are also discussed.

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NORSETTE METHOD IN SOLVING THE NON-STEADY HEAT CONDUCTION PROBLEM Cheng Heming, Wang Honggang, Chen Yongjing 1992, 9(4): 441-442.  Abstract ( )   PDF (157KB) ( )   In this paper, Norsette Method is used to solve the non-steady heat conduction problem. This method prevents the "oscillation" of numerical solution effectively.

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A CERTAIN NUMBER OF ABSOLUTELY STABLE AND HIGH ACCURACY OF SEMI-EXDLICIT DIFFERENCE SCHEMES Zeng Wenping, Wang Ziding 1992, 9(4): 443-444.  Abstract ( )   PDF (134KB) ( )   In this paper, Four classes of three level semi-explieit difference Schemes for solving the dispersive equation u1=auxxx are developed. The orders of the local truncation error are all O(τ2+h2+(τ2)/(h3)) or O(τ2+h4+((τ)/(h))2+τh). The schemes of Ⅰ,Ⅱ and when paramater α≤1, the schemes of Ⅲ. Ⅳ are all shown to be unconditionally stable by the Von Neumann criterion for stability. And thev can be calculated explicitly when necessary boundary value are given.

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NUMERICAL COMPUTATON FOR EXTREME EIGENVALES OF THE PCG ITERATIVE MATRIX Ru Xiangyang, Lei Guangyao 1992, 9(4): 445-447.  Abstract ( )   PDF (227KB) ( )   This paper discusses the relationship between the iterative matrix AM-1 of the preconditioned conjugate gradient (PCG) and the tridiagonal matrix Bs obtained when the PCG iteration terminates. The distribution of eigenvalues of Bs is analysed and, consequently, several properties of eigenvalues of the PCG iterative matrix AM-1 are revealed.

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TWO-HIGH-ORDER ACCURACY EXPLICIT DIFFERENCE SCHEMES FOR SOLVING THE EQUATION OF TOW-DIMENSIONAL PARABOLIC TYPE Zeng Wenping 1992, 9(4): 448-450.  Abstract ( )   PDF (199KB) ( )   In this paper, a two and three level explicit difference schemes with high order accuracy for solving the equation of two-dimensional parabolic type is proposed.

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A NUMERICAL SOLUTION OF THE MATRIX EQUATION AXB-CXD=E Lü Tongxing, Wang Xiaohong 1992, 9(4): 451-454.  Abstract ( )   PDF (227KB) ( )   In this paper, a finite algebraic expression for the solution of matrix equation AXB-CXD=E is derived, and the numerical solutions are given. Finally, the paper gives two calculation examples.

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A VECTORIZED EBE ALGORITHM FOR MATRIX-VECTOR MULTIPLY Deng Shaozhong, Zhou Shuquan, Gao Kehua 1992, 9(4): 455-460.  Abstract ( )   PDF (384KB) ( )   In this paper, based on the work of L.J.Hayes in 1986, a vectorized algorithm of the global stiffness matrix-vector multiply in finite element structural analysis is developed when we in fact don't form the global stiffness matrix. A numerical example by using the method in iterative solution of finite element equations verify it is very efficient.

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THE EFFECT OF TREATMENT OF NEUMANN BOUNDARY CONEITI ONS ON THE ACCURACY OF FINITE DIFFERENCE SOLUTIONS Huang Wei-zhang, Zhang Suo-Chun 1992, 9(4): 461-463.  Abstract ( )   PDF (198KB) ( )   In this paper, we are devoted to a study of the effect of the treatment of Neumann boundary conditions for one-dimensional advection-diffusion equation by the analysis method, and for tow-dimensional Poisson equation by the numerical test method. The reults show that the scheme is first-order accurate in space (i.e. O(h)can be derived first-order accurate difference solution or second-order solution, and the O(h2) or O(h3) scheme is only derived second-order solution.

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THE FINITR VOLUME ELEMENT (FVE) AND MULTIGRID METHOD FOR THE INCOMPRESSIBLE NAVIER-STOKES EQUATIONS Gu Lizhen, Bao Weizhu 1992, 9(4): 464-468.  Abstract ( )   PDF (311KB) ( )   In this paper, We apply FVE method to discrete INS equations with the original variable, In which the bilinear square finite element and the square finite volume are choiced, The discrete schemes of INS equations are presented. The FMV Multigrid algorithem is applied to solve that discrete system, Where DGS iteration is used as smoother, DGS distributive mode for the INS discrete system is also presented. The sample problems for the square cavity flow with Reynolds number Re≤100 are successfully calculated. The numerical solutions show that the results with 1FMV is satisfactory and when Re is not large, The FVE discrete scheme of the conserative INS equations and that of non-conserative INS equations with linearization both can provide almost same accuracy.

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ARTIFICIAL BOUNDARY CONDITIONS FOR THE WAVE EQUATION Cao wei, Lu Jinfu 1992, 9(4): 469-472.  Abstract ( )   PDF (257KB) ( )   We consider the problem of constructing artificial boundary conditions for the wave equation. Two new boundary conditions are presented directly by a difference approximation. The stability of these boundary conditions and their consistency with the analytical boundary conditions are proved. Numericl examples indicate that these boundary conditions work effectively.

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A METHOD OF SOLVING 2-D TURBULENT BOUNDARY LAYER FOR STUDYING BLADE EROSION IN SUSPENDED SOLID PATICLES CENTRIFUGAL FANS Mi Ke, Zhang Bengzhao 1992, 9(4): 473-476.  Abstract ( )   PDF (294KB) ( )   The present paper has derived 2-D turbulent boundray layer differential equations including the effects rotation and curvature to solve gas-phase flow in Blade-to-Blade stream plane of centrifugal fans. Using single-phase-correlation model, we caculate the trails solid particles in blade channel and the balde erosion impacted by solid particles. The computation results show that this boundray layer method agree with practical situations better than the potential flow computation model. It is suitable for engineering caculation.

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THE BEM FOR SOME PROBLEMS IN SOLAR PHYYSICS Yu qin, Kang Fong, Yan Yihua 1992, 9(4): 477-478.  Abstract ( )   PDF (162KB) ( )   The BEM is introduced and applied to solar magnetic force-free field problems. So that the magnetic structure above the sun can be analyzed directly from the observational data. The agreement between calculation and observation shows that the BEM is a useful tool to the solar physics.